RFC 1004 (rfc1004) - Page 1 of 8

Distributed-protocol authentication scheme

Network Working Group                                         D.L. Mills
Request for Comments:  1004                       University of Delaware
                                                              April 1987


              A Distributed-Protocol Authentication Scheme


Status of this Memo

   The purpose of this RFC is to focus discussion on authentication
   problems in the Internet and possible methods of solution.  The
   proposed solutions this document are not intended as standards for
   the Internet at this time.  Rather, it is hoped that a general
   consensus will emerge as to the appropriate solution to
   authentication problems, leading eventually to the adoption of
   standards.  Distribution of this memo is unlimited.


1. Introduction and Overview

   This document suggests mediated access-control and authentication
   procedures suitable for those cases when an association is to be set
   up between multiple users belonging to different trust environments,
   but running distributed protocols like the existing Exterior Gateway
   Protocol (EGP) [2], proposed Dissimilar Gateway Protocol (DGP) [3]
   and similar protocols. The proposed prcedures are evolved from those
   described by Needham and Shroeder [5], but specialized to the
   distributed, multiple-user model typical of these protocols.

   The trust model and threat environment are identical to that used by
   Kent and others [1]. An association is defined as the end-to-end
   network path between two users, where the users themselves are
   secured, but the path between them is not. The network may drop,
   duplicate or deliver messages with errors. In addition, it is
   possible that a hostile user (host or gateway) might intercept,
   modify and retransmit messages. An association is similar to the
   traditional connection, but without the usual connection requirements
   for error-free delivery.  The users of the association are sometimes
   called associates.

   The proposed procedures require each association to be assigned a
   random session key, which is provided by an authentication server
   called the Cookie Jar. The procedures are designed to permit only
   those associations sanctioned by the Cookie Jar while operating over
   arbitrary network topologies, including non-secured networks and
   broadcast-media networks, and in the presence of hostile attackers.
   However, it is not the intent of these procedures to hide the data



Mills